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mereged lexical_cast from trunk r72267 (more optimizations, updated documentation, added tests)

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[SVN r72268]
This commit is contained in:
Antony Polukhin
2011-05-29 19:21:28 +00:00
parent a385c3ec99
commit 1f7147d24b
3 changed files with 243 additions and 52 deletions
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211
include/boost/lexical_cast.hpp
View File

@ -247,13 +247,42 @@ namespace boost
static void check_coverage() {}
};
// No specializations for:
// lcast_src_length<char, signed char>
// lcast_src_length<char, unsigned char>
// lcast_src_length<char, signed char*>
// lcast_src_length<char, unsigned char*>
// lcast_src_length<char, signed char const*>
// lcast_src_length<char, unsigned char const*>
template<>
struct lcast_src_length<char, signed char>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
template<>
struct lcast_src_length<char, unsigned char>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
template<>
struct lcast_src_length<char, signed char*>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
template<>
struct lcast_src_length<char, unsigned char*>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
template<>
struct lcast_src_length<char, signed char const*>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
template<>
struct lcast_src_length<char, unsigned char const*>
{
BOOST_STATIC_CONSTANT(std::size_t, value = 1);
static void check_coverage() {}
};
#ifndef BOOST_LCAST_NO_WCHAR_T
template<>
@ -526,6 +555,10 @@ namespace boost
BOOST_STATIC_ASSERT(!std::numeric_limits<T>::is_signed);
#endif
typedef typename Traits::int_type int_type;
CharT const czero = lcast_char_constants<CharT>::zero;
int_type const zero = Traits::to_int_type(czero);
#ifndef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
// TODO: use BOOST_NO_STD_LOCALE
std::locale loc;
@ -533,47 +566,54 @@ namespace boost
numpunct const& np = BOOST_USE_FACET(numpunct, loc);
std::string const& grouping = np.grouping();
std::string::size_type const grouping_size = grouping.size();
CharT thousands_sep = grouping_size ? np.thousands_sep() : 0;
std::string::size_type group = 0; // current group number
char last_grp_size =
grouping_size == 0 || grouping[0] <= 0 ? CHAR_MAX : grouping[0];
if ( grouping_size && grouping[0] > 0 )
{
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
// Check that ulimited group is unreachable:
BOOST_STATIC_ASSERT(std::numeric_limits<T>::digits10 < CHAR_MAX);
#endif
CharT thousands_sep = np.thousands_sep();
std::string::size_type group = 0; // current group number
char last_grp_size = grouping[0];
char left = last_grp_size;
char left = last_grp_size;
#endif
typedef typename Traits::int_type int_type;
CharT const czero = lcast_char_constants<CharT>::zero;
int_type const zero = Traits::to_int_type(czero);
do
{
#ifndef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
if(left == 0)
do
{
++group;
if(group < grouping_size)
if(left == 0)
{
char const grp_size = grouping[group];
last_grp_size = grp_size <= 0 ? CHAR_MAX : grp_size;
++group;
if(group < grouping_size)
{
char const grp_size = grouping[group];
last_grp_size = grp_size <= 0 ? CHAR_MAX : grp_size;
}
left = last_grp_size;
--finish;
Traits::assign(*finish, thousands_sep);
}
left = last_grp_size;
--left;
--finish;
Traits::assign(*finish, thousands_sep);
}
int_type const digit = static_cast<int_type>(n % 10U);
Traits::assign(*finish, Traits::to_char_type(zero + digit));
n /= 10;
} while(n);
--left;
} else
#endif
--finish;
int_type const digit = static_cast<int_type>(n % 10U);
Traits::assign(*finish, Traits::to_char_type(zero + digit));
n /= 10;
} while(n);
{
do
{
--finish;
int_type const digit = static_cast<int_type>(n % 10U);
Traits::assign(*finish, Traits::to_char_type(zero + digit));
n /= 10;
} while(n);
}
return finish;
}
@ -609,10 +649,10 @@ namespace boost
/* According to [22.2.2.1.2] of Programming languages - C++
* we MUST check for correct grouping
*/
if (grouping_size)
if (grouping_size && grouping[0] > 0)
{
unsigned char current_grouping = 0;
CharT const thousands_sep = grouping_size ? np.thousands_sep() : 0;
CharT const thousands_sep = np.thousands_sep();
char remained = grouping[current_grouping] - 1;
for(;end>=begin; --end)
@ -821,9 +861,13 @@ namespace boost
bool operator<<(bool);
bool operator<<(char);
bool operator<<(unsigned char);
bool operator<<(signed char);
#if !defined(BOOST_LCAST_NO_WCHAR_T) && !defined(BOOST_NO_INTRINSIC_WCHAR_T)
bool operator<<(wchar_t);
#endif
bool operator<<(unsigned char const*);
bool operator<<(signed char const*);
bool operator<<(CharT const*);
bool operator<<(short);
bool operator<<(int);
@ -1050,6 +1094,8 @@ namespace boost
}
bool operator>>(CharT&);
bool operator>>(unsigned char&);
bool operator>>(signed char&);
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
// This #if is in sync with lcast_streambuf_for_target
@ -1091,6 +1137,34 @@ namespace boost
return true;
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator<<(
unsigned char ch)
{
return ((*this) << static_cast<char>(ch));
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator<<(
signed char ch)
{
return ((*this) << static_cast<char>(ch));
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator<<(
unsigned char const* ch)
{
return ((*this) << reinterpret_cast<char const*>(ch));
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator<<(
signed char const* ch)
{
return ((*this) << reinterpret_cast<char const*>(ch));
}
#if !defined(BOOST_LCAST_NO_WCHAR_T) && !defined(BOOST_NO_INTRINSIC_WCHAR_T)
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator<<(
@ -1256,6 +1330,34 @@ namespace boost
return ok;
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator>>(
unsigned char& output)
{
BOOST_STATIC_ASSERT( sizeof(CharT) == sizeof(unsigned char) );
bool const ok = (finish - start == 1);
if(ok) {
CharT out;
Traits::assign(out, *start);
output = static_cast<signed char>(out);
}
return ok;
}
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator>>(
signed char& output)
{
BOOST_STATIC_ASSERT( sizeof(CharT) == sizeof(signed char) );
bool const ok = (finish - start == 1);
if(ok) {
CharT out;
Traits::assign(out, *start);
output = static_cast<signed char>(out);
}
return ok;
}
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
template<typename CharT, class Base, class Traits>
inline bool lexical_stream_limited_src<CharT,Base,Traits>::operator>>(
@ -1312,13 +1414,9 @@ namespace boost
struct lcast_streambuf_for_target
{
BOOST_STATIC_CONSTANT(bool, value =
(
::boost::type_traits::ice_or<
::boost::type_traits::ice_not< is_integral<Target>::value >::value,
is_same<Target, signed char>::value,
is_same<Target, unsigned char>::value
>::value
)
(
::boost::type_traits::ice_not< is_integral<Target>::value >::value
)
);
};
@ -1472,16 +1570,29 @@ namespace boost
);
};
/*
* is_xchar_to_xchar<Target, Source>::value is true, when
* Target and Souce are the same char types, or when
* Target and Souce are char types of the same size.
*/
template<typename Target, typename Source>
struct is_xchar_to_xchar
{
BOOST_STATIC_CONSTANT(bool, value =
(
::boost::type_traits::ice_and<
is_same<Source,Target>::value,
is_char_or_wchar<Target>::value
(
::boost::type_traits::ice_or<
::boost::type_traits::ice_and<
is_same<Source,Target>::value,
is_char_or_wchar<Target>::value
>::value,
::boost::type_traits::ice_and<
::boost::type_traits::ice_eq< sizeof(char),sizeof(Target)>::value,
::boost::type_traits::ice_eq< sizeof(char),sizeof(Source)>::value,
is_char_or_wchar<Target>::value,
is_char_or_wchar<Source>::value
>::value
>::value
)
)
);
};

31
lexical_cast.htm
View File

@ -26,6 +26,8 @@
<a href="#references">References</a></li>
<li>
<a href="#changes">Changes</a></li>
<li>
<a href="#performance">Performance</a></li>
</ul>
<hr>
<h2><a name="motivation">Motivation</a></h2>
@ -87,7 +89,7 @@
For a good discussion of the options and issues involved in string-based
formatting, including comparison of <code>stringstream</code>, <code>lexical_cast</code>,
and others, see Herb Sutter's article, <a href="http://www.gotw.ca/publications/mill19.htm">
<i>The String Formatters of Manor Farm</i></a>.
<i>The String Formatters of Manor Farm</i></a>. Also, take a look at the <a href="#performance">Performance</a> section.
<p>
<hr>
<h2><a name="examples">Examples</a></h2>
@ -267,6 +269,8 @@ Eliminate an overhead of <code>std::locale</code> if your program runs in the "C
<h2><a name="changes">Changes</a></h2>
<h3>May 2011:</h3>
<ul type="square">
<li>Optimizations for "C" and other locales without number grouping.</li>
<li>Better performance and less memory usage for unsigned char and signed char conversions.</li>
<li>Better performance and less memory usage for conversions to arithmetic types.</li>
<li>Better performance and less memory usage for conversions from arithmetic type to arithmetic type.</li>
<li>Directly construct <code>Target</code> from <code>Source</code> on some conversions (like conversions from string to string, from char array to string, from char to char and others).</li>
@ -312,7 +316,30 @@ Eliminate an overhead of <code>std::locale</code> if your program runs in the "C
</ul>
<p>
<hr>
<h2><a name="performance">Performance</a></h2>
This table shows the execution time in milliseconds for 100000 calls of the following string formatters:
<table border="1" width="100%">
<tr>
<tr><td>From->To</td><td> <code>lexical_cast</code> </td><td><code>std::stringstream</code><br>with construction</td><td><code>std::stringstream</code><br>without construction</td><td><code>sscanf</code>/<code>sprintf</code></td></tr>
<tr><td>string->char</td><td bgcolor="#00C000"><1</td><td>91</td><td>7</td><td>10</td></tr>
<tr><td>string->int</td><td bgcolor="#00C000">7</td><td>115</td><td>23</td><td>18</td></tr>
<tr><td>string->unsigned int</td><td bgcolor="#00C000">7</td><td>117</td><td>22</td><td>17</td></tr>
<tr><td>string->bool</td><td bgcolor="#00C000"><1</td><td>104</td><td>19</td><td>10</td></tr>
<tr><td>string->float</td><td>85</td><td>172</td><td>60</td><td bgcolor="#00C000">33</td></tr>
<tr><td>char->string</td><td bgcolor="#00C000">7</td><td>105</td><td>16</td><td>12</td></tr>
<tr><td>int->string</td><td bgcolor="#00C000">15</td><td>131</td><td>21</td><td>17</td></tr>
<tr><td>unsigned int->string</td><td bgcolor="#00C000">14</td><td>125</td><td>21</td><td>17</td></tr>
<tr><td>bool->string</td><td bgcolor="#00C000">7</td><td>122</td><td>24</td><td>12</td></tr>
<tr><td>float->string</td><td>124</td><td>223</td><td>115</td><td bgcolor="#00C000">48</td></tr>
<tr><td>char*->string</td><td bgcolor="#00C000">9</td><td>123</td><td>20</td><td>---</td></tr>
<tr><td>int->int</td><td bgcolor="#00C000"><1</td><td>120</td><td>26</td><td>---</td></tr>
<tr><td>float->float</td><td bgcolor="#00C000"><1</td><td>262</td><td>142</td><td>---</td></tr>
</table>
Fastest results are highlitened with green.
<hr>
<div align="right"><small><i>Copyright &copy; Kevlin Henney, 2000-2005</i></small></div>
<div align="right"><small><i>Copyright &copy; Alexander Nasonov, 2006-2010</i></small></div>
<div align="right"><small><i>Copyright &copy; Antony Polukhin, 2011</i></small></div>

53
lexical_cast_test.cpp
View File

@ -95,6 +95,7 @@ void test_wtraits();
void test_allocator();
void test_wallocator();
#endif
void test_char_types_conversions();
unit_test::test_suite *init_unit_test_suite(int, char *[])
{
@ -137,6 +138,8 @@ unit_test::test_suite *init_unit_test_suite(int, char *[])
suite->add(BOOST_TEST_CASE(&test_wallocator));
#endif
suite->add(BOOST_TEST_CASE(&test_char_types_conversions));
return suite;
}
@ -730,6 +733,12 @@ void test_conversion_from_to_integral()
BOOST_CHECK(lexical_cast<T>("+1") == static_cast<T>(1) );
BOOST_CHECK(lexical_cast<T>("+9") == static_cast<T>(9) );
BOOST_CHECK(lexical_cast<T>("+10") == static_cast<T>(10) );
BOOST_CHECK(lexical_cast<T>("+90") == static_cast<T>(90) );
BOOST_CHECK_THROW(lexical_cast<T>("++1"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("-+9"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("--1"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("+-9"), bad_lexical_cast);
// test_conversion_from_to_integral_for_locale
typedef std::numpunct<char> numpunct;
@ -785,6 +794,11 @@ void test_conversion_from_to_float()
BOOST_CHECK_CLOSE(lexical_cast<T>("+1"), 1, std::numeric_limits<T>::epsilon() );
BOOST_CHECK_CLOSE(lexical_cast<T>("+9"), 9, std::numeric_limits<T>::epsilon()*9 );
BOOST_CHECK_THROW(lexical_cast<T>("++1"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("-+9"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("--1"), bad_lexical_cast);
BOOST_CHECK_THROW(lexical_cast<T>("+-9"), bad_lexical_cast);
}
void test_conversion_from_to_short()
@ -923,3 +937,42 @@ void test_wallocator()
#endif
void test_char_types_conversions()
{
const char c_arr[] = "Test array of chars";
const unsigned char uc_arr[] = "Test array of chars";
const signed char sc_arr[] = "Test array of chars";
BOOST_CHECK(boost::lexical_cast<std::string>(c_arr) == std::string(c_arr));
BOOST_CHECK(boost::lexical_cast<std::string>(uc_arr) == std::string(c_arr));
BOOST_CHECK(boost::lexical_cast<std::string>(sc_arr) == std::string(c_arr));
BOOST_CHECK(boost::lexical_cast<char>(c_arr[0]) == c_arr[0]);
BOOST_CHECK(boost::lexical_cast<char>(uc_arr[0]) == c_arr[0]);
BOOST_CHECK(boost::lexical_cast<char>(sc_arr[0]) == c_arr[0]);
BOOST_CHECK(boost::lexical_cast<unsigned char>(c_arr[0]) == uc_arr[0]);
BOOST_CHECK(boost::lexical_cast<unsigned char>(uc_arr[0]) == uc_arr[0]);
BOOST_CHECK(boost::lexical_cast<unsigned char>(sc_arr[0]) == uc_arr[0]);
BOOST_CHECK(boost::lexical_cast<signed char>(c_arr[0]) == sc_arr[0]);
BOOST_CHECK(boost::lexical_cast<signed char>(uc_arr[0]) == sc_arr[0]);
BOOST_CHECK(boost::lexical_cast<signed char>(sc_arr[0]) == sc_arr[0]);
#ifndef BOOST_LCAST_NO_WCHAR_T
const wchar_t wc_arr[]=L"Test array of chars";
BOOST_CHECK(boost::lexical_cast<std::wstring>(wc_arr) == std::wstring(wc_arr));
BOOST_CHECK(boost::lexical_cast<std::wstring>(c_arr) == std::wstring(wc_arr));
BOOST_CHECK(boost::lexical_cast<std::wstring>(sc_arr) != std::wstring(wc_arr) );
BOOST_CHECK(boost::lexical_cast<std::wstring>(uc_arr) != std::wstring(wc_arr) );
BOOST_CHECK(boost::lexical_cast<wchar_t>(c_arr[0]) == wc_arr[0]);
BOOST_CHECK(boost::lexical_cast<wchar_t>(wc_arr[0]) == wc_arr[0]);
BOOST_CHECK_THROW(boost::lexical_cast<wchar_t>(uc_arr[0]), bad_lexical_cast);
BOOST_CHECK_THROW(boost::lexical_cast<wchar_t>(sc_arr[0]), bad_lexical_cast);
#endif
}